You see this all the time in fantasy, where NotEngland is fighting against NotFrance, but the NotVikings invade, and the NotMongol Horde comes riding across the plains. Cultural analogs are super common. As much as critics like to get all huffy and bitchy about that, there’s nothing inherently wrong with borrowing from familiar real world cultures. As long as it is entertaining you can get away with it.

On the plus side it establishes some fundamentals with the reader easily. You’ve got longbow archers with English sounding names fighting knights with French names, it paints a quick picture. They’ve read a hundred books and seen a dozen movies like that already. Readers are going to subconsciously assume that everything which isn’t pointed out as being different is probably the same as what they’re already expecting. Those are their defaults.

On the downside, it’s been done a million times. But the reason something gets done a million times is because it works. This is a competitive business, so if you’re doing something familiar then you need to make yours stand out somehow (I’d recommend being excellent). If you use a cultural analog which isn’t as familiar for your audience, it is unique, but it may require a bit more work to set the stage. It still creates a visual waypoint, but the audience just might not have as much groundwork laid. There aren’t as many epic fantasies about NotIndia as there are about NotEngland, but people get the idea.

Now critics are going to bitch no matter what you do. If you have a western basis to your fantasy you will be called tired and clichéd (and probably racist) and if you use a non-western basis then you are guilty of cultural appropriation. So as usual, just tell the critics to kiss your ass and get back to writing. Nobody really gives a crap what they think anyway.

Personally, I like borrowing from all sorts of different places. It keeps things interesting, unique, but familiar enough that the reader can concentrate on the important stuff, being entertained rather than being lost.

Another possibility is just making up something entirely unique and original, not based on any Earth culture at all. You are free to do whatever you want. There’s no reference for the readers, so you’ll need to do a good job painting them a picture. Just don’t get so clever with making up new stuff that the readers get confused and lost, adrift on a sea of made up words. If you’re going to write something dense and confusing, where the reader can’t get a bearing, you’d better be one damned compelling wordsmith to keep their interest.

If you are interested in the craft, it definitely worth your time. Read the whole thing.